Class PipedInputStream
java.lang.Object
java.io.InputStream
java.io.PipedInputStream
- All Implemented Interfaces:
Closeable,AutoCloseable
A piped input stream should be connected
to a piped output stream; the piped input
stream then provides whatever data bytes
are written to the piped output stream.
Typically, data is read from a
PipedInputStream
object by one thread and data is written
to the corresponding PipedOutputStream
by some other thread. Attempting to use
both objects from a single thread is not
recommended, as it may deadlock the thread.
The piped input stream contains a buffer,
decoupling read operations from write operations,
within limits.
A pipe is said to be broken if a
thread that was providing data bytes to the connected
piped output stream is no longer alive.- Since:
- 1.0
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected byte[]The circular buffer into which incoming data is placed.protected intThe index of the position in the circular buffer at which the next byte of data will be stored when received from the connected piped output stream.protected intThe index of the position in the circular buffer at which the next byte of data will be read by this piped input stream.protected static final intThe default size of the pipe's circular input buffer. -
Constructor Summary
ConstructorsConstructorDescriptionCreates aPipedInputStreamso that it is not yet connected.PipedInputStream(int pipeSize) Creates aPipedInputStreamso that it is not yet connected and uses the specified pipe size for the pipe's buffer.Creates aPipedInputStreamso that it is connected to the piped output streamsrc.PipedInputStream(PipedOutputStream src, int pipeSize) Creates aPipedInputStreamso that it is connected to the piped output streamsrcand uses the specified pipe size for the pipe's buffer. -
Method Summary
Modifier and TypeMethodDescriptionintReturns the number of bytes that can be read from this input stream without blocking.voidclose()Closes this input stream and releases any system resources associated with the stream.voidconnect(PipedOutputStream src) Causes this piped input stream to be connected to the piped output streamsrc.intread()Reads the next byte of data from this piped input stream.intread(byte[] b, int off, int len) Reads up tolenbytes of data from this piped input stream into an array of bytes.protected voidreceive(int b) Receives a byte of data.Methods declared in class java.io.InputStream
mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, skip, skipNBytes, transferTo
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Field Details
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PIPE_SIZE
protected static final int PIPE_SIZEThe default size of the pipe's circular input buffer.- Since:
- 1.1
- See Also:
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buffer
protected byte[] bufferThe circular buffer into which incoming data is placed.- Since:
- 1.1
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in
protected int inThe index of the position in the circular buffer at which the next byte of data will be stored when received from the connected piped output stream.in < 0implies the buffer is empty,in == outimplies the buffer is full- Since:
- 1.1
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out
protected int outThe index of the position in the circular buffer at which the next byte of data will be read by this piped input stream.- Since:
- 1.1
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Constructor Details
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PipedInputStream
Creates aPipedInputStreamso that it is connected to the piped output streamsrc. Data bytes written tosrcwill then be available as input from this stream.- Parameters:
src- the stream to connect to.- Throws:
IOException- if an I/O error occurs.
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PipedInputStream
Creates aPipedInputStreamso that it is connected to the piped output streamsrcand uses the specified pipe size for the pipe's buffer. Data bytes written tosrcwill then be available as input from this stream.- Parameters:
src- the stream to connect to.pipeSize- the size of the pipe's buffer.- Throws:
IOException- if an I/O error occurs.IllegalArgumentException- ifpipeSize <= 0.- Since:
- 1.6
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PipedInputStream
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PipedInputStream
public PipedInputStream(int pipeSize) Creates aPipedInputStreamso that it is not yet connected and uses the specified pipe size for the pipe's buffer. It must be connected to aPipedOutputStreambefore being used.- Parameters:
pipeSize- the size of the pipe's buffer.- Throws:
IllegalArgumentException- ifpipeSize <= 0.- Since:
- 1.6
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Method Details
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connect
Causes this piped input stream to be connected to the piped output streamsrc. If this object is already connected to some other piped output stream, anIOExceptionis thrown.If
srcis an unconnected piped output stream andsnkis an unconnected piped input stream, they may be connected by either the call:snk.connect(src)or the call:
src.connect(snk)The two calls have the same effect.
- Parameters:
src- The piped output stream to connect to.- Throws:
IOException- if an I/O error occurs.
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receive
Receives a byte of data. This method will block if no input is available.- Parameters:
b- the byte being received- Throws:
IOException- If the pipe isbroken,unconnected, closed, or if an I/O error occurs.- Since:
- 1.1
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read
Reads the next byte of data from this piped input stream. The value byte is returned as anintin the range0to255. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.- Specified by:
readin classInputStream- Returns:
- the next byte of data, or
-1if the end of the stream is reached. - Throws:
IOException- if the pipe isunconnected,broken, closed, or if an I/O error occurs.
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read
Reads up tolenbytes of data from this piped input stream into an array of bytes. Less thanlenbytes will be read if the end of the data stream is reached or iflenexceeds the pipe's buffer size. Iflenis zero, then no bytes are read and 0 is returned; otherwise, the method blocks until at least 1 byte of input is available, end of the stream has been detected, or an exception is thrown.- Overrides:
readin classInputStream- Parameters:
b- the buffer into which the data is read.off- the start offset in arraybat which the data is written.len- the maximum number of bytes to read.- Returns:
- the total number of bytes read into the buffer, or
-1if there is no more data because the end of the stream has been reached. - Throws:
NullPointerException- Ifbisnull.IndexOutOfBoundsException- Ifoffis negative,lenis negative, orlenis greater thanb.length - offIOException- if the pipe isbroken,unconnected, closed, or if an I/O error occurs.- See Also:
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available
Returns the number of bytes that can be read from this input stream without blocking.- Overrides:
availablein classInputStream- Returns:
- the number of bytes that can be read from this input stream
without blocking, or
0if this input stream has been closed by invoking itsclose()method, or if the pipe isunconnected, orbroken. - Throws:
IOException- if an I/O error occurs.- Since:
- 1.0.2
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close
Closes this input stream and releases any system resources associated with the stream.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classInputStream- Throws:
IOException- if an I/O error occurs.
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